Swapping MTH PS-2 tenders

If I remember correctly about the matter of swapping PS-2 tenders, you must have the correct color dots matched up together. There is a small color dot or something on each PS-2 tender & engine and only a tender with a matching color should be used, example; green dot on tender with a green dot on engine, or an orange dot on engine with an orange dot on tender. Look for these on the bottom of the engine and tender.

It has something to do with electronic circuits.

Lee Fritz

I think there are some differences between different models and/or product lines.  I know that MTH strongly advises that you never do this, I suspect they have a good reason.

I am not 100% positive that you can mix and match MTH PS-2 tenders but I thought that I read an article somewhere about being able to do that.

Check with Barry Broskowicz, he is the DCS guru on here.

Lee Fritz

DO NOT  DO NOT  swap tenders.  I have made wiring diagrams of all my Proto-2 engines and have found the pinouts to be different on many of them. 

Thanks Bob, MTH told us the same thing at the ASC classes, that's why I don't do that.

Here is why.  Some steam have PS-2 5V boards and other have PS-2 3V, so you would be mixing battery voltages (2.4V versus 8.4V or speakers 4 ohm versus 16 ohm).  Some steam have boards in the engine (primarily PS-2 5V) and others in the tender.  These different configuration can cause issues.

The last item, is that wiring could be different even if like in other ways.  Usually you can match if in the same catalog and similar engines.

So it is really frowned upon to test by swapping tenders.  Placing AC power on the DC circuit will fry both boards rapidly.  Other issues could cause damage to certain circuits.

Now if you open the tender and they are identical in wiring and type of system, you can swap tenders fine.  G

Stop and think about it,,,some engines have different features that would cause who knows what kind of trouble!  IIRC, you could swap certain PS1 tenders, if the features were all the same.   I would think that trying to mix a pair of different PS2s not all that different than my recent UP Lionel exploding die-cast tender, but in an electrical context! 

I believe Proto-1's  4 cable pin layout is the same for all steam locos. Again Proto-2 is not.

Good point about the location of the boards George, that would certainly change the wiring.

So far I have only seen the tenders with what looks like a portable phone battery pack, probably the 2.4 volt PS-2 tender. I didn't know that there are as many versions of the PS-2 tenders as what is being described on here.

I have the wall charger for the PS-2 engine, and there are two plugs on it, so one is for the 2.4 volt and the other for the 5 volt, I am guessing?

Lee Fritz

You guessed correctly Lee, that's what the other plug is for.

Yes, PS-1 are wired the same.  AC inputs from engine and motor inputs to engine.

Different features would not matter in the sound file.  That won't hurt anything as long as wires are the same.

Yep, the early PS-2 is called the 5V system because the processors all used 5V.  The battery was the 8.4V rechargeable (round charge port).

The revised PS-2 is the 3V system because main processors and memory run on 3V.  The battery is a 2.4V AA rechargeable (rectangular port).  Even if matching 3V to 3V you can have some wiring difference that can cause damage.  That is why you have to check.  G

However, if you have two of the same, identical engines, tender swapping is not a problem...correct?  Thanks,   Joe

Correct.  G